Building A Heading Sensor Resistant To Magnetic Disturbances

March 6, 2026 by 1 Comment

Light aircraft often use a heading indicator as a way to know where they’re going. Retired instrumentation engineer [Don Welch] recreated a heading indicator of his own, using cheap off-the-shelf hardware to get the job done.

The heart of the build is a Teensy 4.0 microcontroller. It’s paired with a BNO085 inertial measurement unit (IMU), which combines a 3-axis gyro, 3-axis accelerometer, and 3-axis magnetometer into a single package. [Don] wanted to build a heading indicator that was immune to magnetic disturbances, so ignored the magnetometer readings entirely, using the rest of the IMU data instead.

Upon startup, the Teensy 4.0 initializes a small round TFT display, and draws the usual compass rose with North at the top of the display. Any motion after this will update the heading display accordingly, with [Don] noting the IMU has a fast update rate of 200 Hz for excellent motion tracking. The device does not self-calibrate to magnetic North; instead, an encoder can be used to calibrate the device to match a magnetic compass you have on hand. Or, you can just ensure it’s already facing North when you turn it on.

Thanks to the power of the Teensy 4.0 and the rapid updates of the BNO085, the display updates are nicely smooth and responsive. However, [Don] notes that it’s probably not quite an aircraft-spec build. We’ve featured some interesting investigations of just how much you can expect out of MEMS-based sensors like these before, too.

Continue reading “Building A Heading Sensor Resistant To Magnetic Disturbances” →

Ebike Charges At Car Charging Stations

March 5, 2026 by 2 Comments

Electric vehicles are everywhere these days, and with them comes along a whole slew of charging infrastructure. The fastest of these are high-power machines that can deliver enough energy to charge a car in well under an hour, but there are plenty of slower chargers available that take much longer. These don’t tend to require any specialized equipment which makes them easier to install in homes and other places where there isn’t as much power available. In fact, these chargers generally amount to fancy extension cords, and [Matt Gray] realized he could use these to do other things like charge his electric bicycle.

To begin the build, [Matt] started with an electric car charging socket and designed a housing for it with CAD software. The housing also holds the actual battery charger for his VanMoof bicycle, connected internally directly to the car charging socket. These lower powered chargers don’t require any communication from the vehicle either, which simplifies the process considerably. They do still need to be turned on via a smartphone app so the energy can be metered and billed, but with all that out of the way [Matt] was able to take his test rig out to a lamppost charger and boil a kettle of water.

After the kettle experiment, he worked on miniaturizing his project so it fits more conveniently inside the 3D-printed enclosure on the rear rack of his bicycle. The only real inconvenience of this project, though, is that since these chargers are meant for passenger vehicles they’re a bit bulky for smaller vehicles like e-bikes. But this will greatly expand [Matt]’s ability to use his ebike for longer trips, and car charging infrastructure like this has started being used in all kinds of other novel ways as well.

Continue reading “Ebike Charges At Car Charging Stations” →

California’s Problematic Attempt To Add Age-Verification To Software

March 5, 2026 by 13 Comments

Last year California’s Digital Age Assurance Act (AB 1043) was signed into law, requiring among other things that operating system providers implement an API for age verification purposes. With the implementation date of January 1, 2027 slowly encroaching this now has people understandably agitated. So what are the requirements, and what will its impact be, as it affects not only OS developers but also application stores and developers?

The required features for OS developers include an interface at account setup during which the person indicates which of the four age brackets they fit into. This age category then has to be used by application developers and application stores to filter access to the software. Penalties for non-compliance go up to $2,500 per affected child if the cause is neglect and up to $7,500 if the violation was intentional.

As noted in the Tom’s Hardware article, CA governor Newsom issued a statement when signing the unanimously passed bill, saying that he hopes the bill gets amended due to how problematic it would be to implement and unintended effects. Of course, the bigger question is whether this change requires more than adding a few input fields and checkboxes to an OS’ account setup and an API call or two.

Continue reading “California’s Problematic Attempt To Add Age-Verification To Software” →

Prevent Your Denon Receiver Turning On From Rogue Nvidia Shield CEC Requests

March 5, 2026 by 7 Comments

In theory HDMI’s CEC feature is great, as it gives HDMI devices the ability to do useful things such as turning on multiple HDMI devices with a single remote control. Of course, such a feature will inevitably feature bugs. A case in point is the Nvidia Shield which has often been reported to turn on other HDMI devices that should stay off. After getting ticked off by such issues one time too many, [Matt] decided to implement a network firewall project to prevent his receiver from getting messed with by the Shield.

The project is a Python-based network service that listens for the responsible rogue HDMI-CEC Zone 2 requests and talks with a Denon/Marantz receiver to prevent it from turning on unnecessarily. Of course, when you want these Zone 2 requests to do their thing you need to disable the script.

That said, HDMI-CEC is such a PITA that people keep running into issues like these over and over again, to the point where people are simply disabling the feature altogether. That said, Nvidia did recently release a Shield update that’s claimed to fix CEC issues, so maybe this is one CEC bug down already.

Capacitor Memory Makes Homebrew Relay Computer Historically Plausible

March 5, 2026 by 12 Comments

It’s one thing to create your own relay-based computer; that’s already impressive enough, but what really makes [DiPDoT]’s design special– at least after this latest video— is swapping the SRAM he had been using for historically-plausible capacitor-based memory.

A relay-based computer is really a 1940s type of design. There are various memory types that would have been available in those days, but suitable CRTs for Williams Tues are hard to come by these days, mercury delay lines have the obvious toxicity issue, and core rope memory requires granny-level threading skills. That leaves mechanical or electromechanical memory like [Konrad Zuse] used in the 30s, or capacitors. he chose to make his memory with capacitors.

It’s pretty obvious when you think about it that you can use a capacitor as memory: charged/discharged lets each capacitor store one bit. Charge is 1, discharged is 0. Of course to read the capacitor it must be discharged (if charged) but most early memory has that same read-means-erase pattern. More annoying is that you can’t overwrite a 1 with a 0– a separate ‘clear’ circuit is needed to empty the capacitor. Since his relay computer was using SRAM, it wasn’t set up to do this clear operation.

He demonstrates an auto-clearing memory circuit on breadboard, using 3 relays and a capacitor, so the existing relay computer architecture doesn’t need to change. Addressing is a bit of a cheat, in terms of 1940s tech, as he’s using modern diodes– though of course, tube diodes or point-contact diodes could conceivably pressed into service if one was playing purist. He’s also using LEDs to avoid the voltage draw and power requirements of incandescent indicator lamps. Call it a hack.

He demonstrates his circuit on breadboard– first with a 4-bit word, and then scaled up to 16-bit, before going all way to a massive 8-bytes hooked into the backplane of his Altair-esque relay computer. If you watch nothing else, jump fifteen minutes in to have the rare pleasure of watching a program being input via front panel with a complete explanation. If you have a few extra seconds, stay for the satisfyingly clicky run of the loop. The bonus 8-byte program [DiPDoT] runs at the end of the video is pure AMSR, too.

Yeah, it’s not going to solve the rampocalypse, any more than the initial build of this computer helped with GPU prices. That’s not the point. The point is clack clack clack clack clack, and if that doesn’t appeal, we don’t know what to tell you.

Continue reading “Capacitor Memory Makes Homebrew Relay Computer Historically Plausible” →

Railway End Table Powered By Hand Crank

March 5, 2026 by 6 Comments

Most end tables that you might find in a home are relatively static objects. However, [Peter Waldraff] of Tiny World Studios likes to build furniture that’s a little more interesting. Thus came about this beautiful piece with a real working railway built right in.

The end table was built from scratch, with [Peter] going through all the woodworking steps required to assemble the piece. The three-legged wooden table is topped with a tiny N-scale model railway layout, and you get to see it put together including the rocks, the grass, and a beautiful epoxy river complete with a bridge. The railway runs a Kato Pocket Line trolley, but the really neat thing is how it’s powered.

[Peter] shows us how a small gearmotor generator was paired with a bridge rectifier and a buck converter to fill up a super capacitor that runs the train and lights up the tree on the table. Just 25 seconds of cranking will run the train anywhere from 4 to 10 minutes depending on if the tree is lit as well. To top it all off, there’s even a perfect coaster spot for [Peter]’s beverage of choice.

It’s a beautiful kinetic sculpture and a really fun way to build a small model railway that fits perfectly in the home. We’ve featured some other great model railway builds before, too.

Continue reading “Railway End Table Powered By Hand Crank” →

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Beginner’s Guide To Split Keyboards

March 5, 2026 by 7 Comments

Curious about split keyboards, but overwhelmed by the myriad options for every little thing? You should start with [thehaikuza]’s excellent Beginner’s Guide to Split Keyboards.

Three different split keyboards.
Image by [thehaikuza] via reddit
Your education begins with the why, so you can skip that if you must, but the visuals are a nice refresher on that front.

He then gets into the types of keyboards — you got your standard row-staggered rectangles that we all grew up on, column-staggered, and straight-up ortholinear, which no longer enjoy the popularity they once did.

At this point, the guide becomes a bit of a Choose Your Own Adventure story. If you want a split but don’t want to learn to change much if at all about your typing style, keep reading, because there are definitely options.

But if you’re ready to commit to typing correctly for the sake of ergonomics, you can skip the Alice and other baby ergo choices and get your membership to the light side. First are features — you must decide what you need to get various jobs done. Then you learn a bit about key map customization, including using a non-QWERTY layout. Finally, there’s the question of buying versus DIYing. All the choices are yours, so go for it!

Via reddit

Continue reading “Keebin’ With Kristina: The One With The Beginner’s Guide To Split Keyboards” →